Declining insect populations affecting migratory birds

Insect decline globally driven by land-use change, climate change, pollution: Report

- Chin Hui Shan

The season for bird migration has begun, with cooler weather descending upon the Northern Hemisphere, sending birds on their long journeys south to places like Singapore to escape the winter chill. Between August and March, these feathered voyagers draw plenty of attention from birdwatchers and groups campaigning for the conservation of wetland habitats where the birds stop and refuel.

But a new UN report has highlighted a critical aspect of migratory bird survival - the decline of insects. The report has said that dwindling insect abundance, biomass and diversity are contributing to population losses among migratory birds, especially those that rely on insects as their main source of food during their migration.

According to the report, which cited other studies, 10 per cent of insects are threatened with extinction globally.

It also noted that about 11 per cent of all migratory land birds and waterbirds are listed as threatened or near threatened on the International Union for Conservation of Nature Red List of Threatened Species, or IUCN Red List. In addition, bird species dependent on insects for food have declined drastically over the last 50 years.

Insect decline worldwide is mainly driven by land-use change, climate change and pollution, the report prepared by the Convention on the Conservation of Migratory Species of Wild Animals - a biodiversity treaty of the UN - said.

Though Singapore is better known for hosting migratory shorebirds - which are less impacted by insect decline due to their diet of worms and crustaceans in wetlands - insect decline may affect the migratory land birds, as well as have an effect on ecosystems here.

Migratory land birds can be found in places such as the Botanic Gardens and Pasir Ris Park.